1. Field of the Invention
The present invention relates to a fan and a frame thereof, and more particularly to a fan and a frame thereof for guiding airflow away from the fan and reducing vortex.
2. Description of the Related Art
As the performance of electronic devices continue to enhance, heat dissipating devices and heat dissipating systems are playing more critical roles within the electronic devices. Poor heat dissipation can lead to damage or failure to the electronic devices.
Heat dissipating devices play an even more important role for microelectronic elements and devices, (e.g. integrated circuit, IC). Due to the increase of integration and advancement of packaging technology, integrated circuit area keeps being reduced and heat per unit area thus keeps being increased. Thus, high efficient heat dissipating devices have been under active development by those in the field.
Referring to FIG. 1A, a cross section view of a conventional axial fan and FIG. 1B, a schematic illustration of a direction of airflow of FIG. 1A are shown. Generally, an axial fan 1 has a frame 11 and a motor base 14 which are connected to each other by several ribs 13. When an airflow f enters an airflow inlet 16 of an axial fan 1 in a vertical direction (as shown in FIG. 1B, arrow X1), an impeller 12 of the axial fan 1 rotates to change the original direction of the airflow f (as shown in FIG. 1B, arrow X2). Then the airflow f passes through the ribs 13 (as shown in FIG. 1B, arrow X3). However, the ribs 13 can not completely guide the airflow back to the vertical direction. Thus, the airflow f of the axial fan 1 exiting from the airflow outlet 17 is not in the vertical direction, as indicated by arrow X4 in FIG. 1B. The airflow f has a tangent component which causes vortex v. Therefore, loss of kinetic energy of the axial fan 1 is raised, and efficiency of heat dissipation is reduced. If more axial fans 1 are provided to achieve adequate heat dissipation effect, then costs and noise will be increased. In addition, axial fans 1 are heat sources. It requires additional energy to dissipate heat generated from the axial fans.